feat(run): use strategy from config

By using the abstract `Strategy`, we find the one specified in the
config file. This is also how `labgrid-client` works[1].

[1]: https://github.com/labgrid-project/labgrid/blob/6b541210c6063e97d81e257d2d6bda1444d9ec78/labgrid/remote/client.py#L800